1. Field of the Invention
The present invention relates to an integrated multi-layer top strap for a ski.
2. The Prior Art
U.S. Pat. No. 5,160,158 discloses a ski with a top strap and a bottom strap. A core is located between these straps and is connected with the plies of the top and bottom strap by means of an adhesive layer, which consists of the same plastic material, in particular plastic foam, as the side faces on both sides of the core. The surfaces of the core and the surfaces of the top and bottom strap facing towards said core are provided with cavities to receive the plastic foam that forms the adhesive layer. Such a ski can be produced in a cost-effective manner, but, due to extreme stresses caused by the elastic properties of the plastic foam, which also forms the pair of side faces, the side faces may be destroyed prematurely.
Furthermore, from German Patent DE-A1-20 33 845 it is known to produce a ski with a shell having an approximately U-shaped cross section, the shanks of which, in order to close an inner hollow space, are provided with a plate forming a parallel plane to the running surface layer. The intermediate spaces between a core inserted in the inner hollow space, and in particular the shanks of the U-shaped shell, are filled with a plastic material, in particular a plastic foam. For perfect production of the outer surfaces of the ski, high demands are being made on the molds required for the production of the side faces.
Furthermore, it is disclosed in U.S. Pat. No. 5,000,475 that in the inner hollow space of a ski consisting of a shell and a cover plate forming the running surface, a core is inserted and that the intermediate spaces between the core and the shanks of the U-shaped cross section of the shell are filled with an elastically deformable, in particular damping, plastic material. The disadvantage of this known embodiment of a ski is that the bonding materials between the surfaces of the core and the base of the shell or the running surface layer or the bottom strap must be produced independently from the production or the filling of the intermediate spaces. This causes different bonding properties which lead to inner stresses inside the ski or to a delamination of said ski.